[Scons-users] Building object files in multiple environments

[Dan Čermák]

Hi Folks,

I am currently using SCons for a big mono-repo C++ Firmware, where I
have lots of common source files and then a directory where the actual
firmware for each device is (this is just a .cpp file with device
specific configurations and the appropriate high-level logic).

For illustration purposes, the directory structure looks something like
this:
.
├── devices
│   ├── Device_A
│   │   ├── main.cpp
│   │   ├── SConscript
│   │   ├── uart.cpp
│   │   └── uart.hpp
│   ├── Device_B
│   │   ├── main.cpp
│   │   └── SConscript
│   └── SConscript
├── spi
│   └── config.cpp
├── uart
│   └── uart.cpp
├── util
│   └── endian.c
└── SConstruct

The idea behind this is that everything outside of 'devices' is
considered as common files and build into object files. Every
subdirectory of devices should have a SConscript that creates a single
binary file (this is the firmware for the specific device) that is
linked with the common object files.

I have achieved this by creating object files for every cpp file not in
devices/ and passing them to the SConscript in devices/. However, there
is a catch: I would like to build everything under devices with an
additional include path (the top level directory of the project) which
should not be propagated to the common object files. I therefore tried
creating a clone of the environment for each device in
devices/SConscript and then doing the following in
devices/Device_A/SConscript:

Import('env_clone', 'obj')

local_obj = env_clone.Object(Glob('*.cpp'))
prog = env_clone.Program('Device_A_bin', local_obj + obj)

Return('prog')

where env_clone is the cloned environment with the additional include
path and obj the list of object files that are common to all
devices (which have been created in the environment env from which
env_clone was cloned). This however causes SCons to complain, that there
are object files in multiple environments with the same build command.


My guess is, that my solution of cloning environments is not the correct
way. Does someone have an idea how to achieve this with SCons?


Thanks in advance,

Dan